Here at Logic4training, we provide you with as much help and advice as we can and give detailed overviews of the training and assessments that we provide.

We have put together some helpful information on our Combustion Performance Analysis (CPA1) training and assessment so you can begin your course with confidence.

Do You Work with Central Heating Boilers and Water Boilers?

Did you know that Combustion Performance Analysis (CPA1) training and assessment is now compulsory for all Gas Safe Registered engineers who carry out work on Central Heating Boilers and Water Heaters (CENWAT) or Gas Fires and Space Heaters (HTR1)?

Gas engineers may be required to undertake combustion performance analysis (CPA1) when carrying out any of the following types of work:

  • Commissioning a new installation (where required by the appliance manufacturer)
  • Re-commissioning after servicing or after replacement of parts
  • When determining service requirements


What is Combustion Performance Analysis (CPA1) Training?

Combustion Performance Analysis (CPA1) training is based on the requirements of British Standard (BS) 7967 Parts 1 -4, the assessment is designed to test an engineer’s competence to undertake and interpret the results of a combustion performance analysis, obtained across a range of domestic gas appliances including flueless, open flued & room sealed appliances.


How to Use a Portable Electronic Combustion Analyser?

A combustion analyser takes a sample of the combustion products and measures the levels of CO, CO2, CO/CO2 ratio, oxygen and the flue gas temperature.

For the majority of domestic appliances, it is the CO/COratio that is used to determine whether combustion is correct or the appliance requires attention e.g. servicing.

Possible reasons for poor combustion include:

  • Lack of maintenance e.g. blocked primary air-port or heat exchanger, dirt or debris on fan or burner
  • Defective or damaged gas or combustion components e.g. split burner, distorted heat exchanger etc.
  • Incorrect gas rate or burner pressure

Where the cause of the poor combustion analysis cannot be rectified by inspection, servicing, cleaning or adjusting, the appliance manufacturer should be consulted and the appliance dealt with in accordance with the Gas Industry Unsafe Situations Procedure (GSUSP).


How to Get a Sample of the Products of Combustion?

Prior to obtaining a sample of the products of combustion the appliance should normally be allowed to operate for at least 10 minutes, this is to ensure the appliance is at normal operating temperature and levels of CO and CO2 produced have stabilised.

During this time the analyser must be prepared for use by turning on and purging the sampling probe and hose, this normally takes 1-2 minutes.


Did You Know?

Some boiler manufacturers will require the appliance to be put into ‘service mode’ or operate at maximum gas rate prior to obtaining a sample.

The sample must be obtained from within the combustion stream with the sampling probe normally inserted 200mm into the flue, this ensures the combustion products are well mixed and an accurate sample is taken.


How to Get a Sample of the Products of Combustion for Open Flued Appliances?

For open flued appliances, the most convenient sampling point is normally via the draught diverter, with room sealed appliances, there are two options how to obtain a sample:

  • Where the appliance is fan assisted and incorporates an integral flue gas sampling point (normally as part of the flue elbow) the sample should be taken from that point
  • Where there is no sample point provided and terminal is accessible the analyser probe can be inserted in the flue discharge duct in the flue terminal

Where a room sealed appliance does not incorporate an integral flue gas sampling point and the terminal is not easily accessible e.g. in a high rise building, it will not be possible to obtain a sample of the combustion products.

CPA1 training and assessment is included within the CCN1 course, for more information about our range of gas courses, contact us today.

Logic4trade sells flue gas analysers, necessary for combustion performance analysis. Click here to find out more.

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